System and Method for Allocating Bandwidth in Remote Equipment on a Passive Optical Network

ABSTRACT

The present disclosure provides a system and method for allocating bandwidth in remote equipment on a passive optical network (PON), wherein the system includes an optical line terminal (OLT), which monitors the acceptance of traffic requesting the PON remote equipment for service and configures through signaling control the parameters for the operation of classifying, shaping, and scheduling the traffic in the remote equipment, and a remote equipment which classifies, shapes, and schedules the accepted traffic based on the parameters configured by the OLT and allocates a proper bandwidth to the accepted traffic, and outputs the traffic in the scheduled order. The present disclosure helps ensure the bandwidth and delay requirements of individual traffic flows in the PON remote equipment are met and interaction between traffic of the same or different service class groups is eliminated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is claiming priority of Chinese Application No.200610058167.9 filed Mar. 8, 2006, entitled “A System and Method forAllocating Bandwidth in Remote Equipment on Passive Optical Network,”which application is incorporated by reference herein in its entirety.

BACKGROUND

The present disclosure relates to the optical communication networkfield, and more particularly to a system and method for allocatingbandwidth in remote equipment on a passive optical network (PON).

The conventional access network technologies are copper cable-based e.g.cable modem (CM) or asymmetric digital subscriber loop (ADSL) making itimpossible to further improve the data rate. To accommodate futuregrowth in users' multimedia and real-time services, fiber to the home(FTTH) is one of the solutions to this bandwidth bottleneck. As afiber-based broadband access technology, PON is the most importantapproach to FTTH. A typical architecture of the PON is illustrated inFIG. 1.

Currently there are three types of PONs, e.g. asynchronous transfer mode(ATM)-based PON (APON) according to ITU-T recommendation G.983,Ethernet-based PON (EPON) according to IEEE standard 802.3ah, andGigabit PON (GPON) according to ITU-T recommendation G.984. These threePON technologies are now the focus of the broadband optical accessnetwork technologies.

As is typical of the EPON architecture, one optical line terminal (OLT)is connected to a number of optical network units (ONUs) or opticalnetwork terminals (ONTs) via a shared optical fiber channel. EPON isavailable in various topologies, such as tree, ring, and bus topologies,of which the tree topology is used most commonly. To the extent nomisunderstanding may be caused, the ONU and ONT are collectively calledONU hereafter.

In an EPON, the downstream transmission (OLT→ONU) is made bypoint-to-multipoint broadcast using a separate wavelength. Traffic goingupstream (ONU→OLT) is routed in a multipoint-to-point manner and adoptstime division multiple access (TDMA) technology so that each ONU takes aseparate communication timeslot to avoid any conflicts. All of the ONUsinvolved in the transmission form a transmission cycle that generallyhas a fixed length.

Though there are international standards and products for the three PONtechnologies, they are defective in that the encapsulation efficiency ofIP packets at the data link layer and the quality of service (QoS) arelow, and label forwarding is not supported.

A new PON technology is disclosed in Method for Operating and Managing aPassive Optical Network (Chinese Patent No. 1592302), wherein thegeneralized multi-protocol label switching (GMPLS) technology isintroduced into the PON to improve communication efficiency, QoS, andpacket forwarding speed. Furthermore, its introduction of theconnection-oriented characteristic (label switching path) makes itpossible to use the integrated service (IntServ) model in the PON. Therole of the IntServ model is to establish a connection in the networkfor each traffic and to reserve some resources for absolute QoSassurance. This model cannot be used in a core network where traffic isheavy, but is only applicable to a smaller network, such as accessnetwork.

One of the existing methods for bandwidth allocation in the PON isadopting the differentiated service (DiffServ) model as the servicemodel in an EPON. The DiffServ model reduces its requirement on networkequipment processing capability and thereby improves the network datatransmission rate by grouping the traffic into a limited number ofpriority classes. This model is suitable for a core network. However,the DiffServ can only provide a differentiated service model on a largescale and cannot ensure the QoS of each traffic flow. In the existingEPON technology, traffic is first pooled within ONUs based on theservice class and is then placed into different queues for transmission.The OLT assigns a transmit timeslot to each ONU according to the queuingstate reported by each ONU. When the transmit timeslot arrives, thequeue scheduling mechanism within the ONU will assign a bandwidth toeach service class. The scheduling mechanism typically comprises apriority scheduler and a generalized processor sharing-based scheduler.

The defect of this PON bandwidth allocation method is that the bandwidthis scheduled within the ONU based on the service class. Though it iseasy to implement, it can only ensure relatively fair access betweendifferent service classes and cannot guarantee fair access amongdifferent traffic flows. Because the PON access network directly facesthe subscribers, who have various complex applications that compete forlimited bandwidth, these applications have varied flow characteristicsand QoS requirements. In some cases, some application data flows maypreemptively seize the bandwidth by increasing the amount of datatransmission while other normal data flows are unable to get services.In other cases, some applications have so many data flows that they maycause network congestion, leading to insufficient services for all flowsdespite the fact that the network can fully meet the servicerequirements of some of these flows. The method is incapable of flowcontrol and access permission control and may cause a service QoSproblem when the load on the network is heavy.

Another PON bandwidth allocation method is adopting ATM as the datacarrier protocol in an APON. The ATM technology allows a separateconnection to be established between the OLT and ONU for each flow aswell as reservation of resources. The technology separates andaggregates the traffic flows via virtual path/virtual channel (VP/VC).The ATM technology provides a good solution to flow control, QoSassurance, security, and improvement of switching speed and billing inan access network. However, its internet protocol (IP) packetencapsulation efficiency may be too low and the protocol layer may becomplex. In view of the importance of IP as the future integratedmulti-task platform, the ATM technology may no longer be a suitablecarrier protocol for an IP-based optical access network. Therefore, theAPON technology may be gradually declining.

Still another method for PON bandwidth allocation is the GPONencapsulation mode (GEM)-based GPON that adopts the framing methodsimilar to general framing procedure (GFP). This method has the samecharacteristics as the ATM method in that both are optimized for timedivision multiplexed (TDM) services. As with the ATM-based solution,this PON bandwidth allocation method is inefficient in supporting IP andis relatively complicated to implement.

SUMMARY

The present disclosure aims to provide a device and method forallocating bandwidth in PON remote equipment so that the bandwidth anddelay requirement of each flow in the PON remote equipment is met, andinteraction between traffic of the same or different service groups iseliminated.

According to an embodiment, the present disclosure provides a system forallocating bandwidth in the PON remote equipment. The system used forallocating bandwidth to a plurality of remote equipment on a passiveoptical network (PON) and comprising:

an optical line terminal (OLT) that controls the acceptance of trafficrequesting service by the PON remote equipment and, through signalingcontrol, classifies, shapes, and schedules the traffic in the remoteequipment; and

wherein the remote equipment classifies, shapes, and schedules thereceived traffic based on the parameters configured by the OLT,allocates a bandwidth to the received traffic, and outputs the trafficin the scheduled order.

The present disclosure also provides a method for allocating bandwidthin passive optical network (PON) remote equipment, comprising:

configuring, within the PON remote equipment, the parameters forclassifying, shaping and scheduling operations; and

the PON remote equipment classifying, shaping, and scheduling thereceived traffic based on the configured parameters, allocating acorresponding bandwidth to the received traffic, and outputting thetraffic in the scheduled order.

As we can see from the above technical solution, by adopting the IntServmodel in the ONU to classify, shape, and schedule the accepted traffic,the present disclosure achieves the management particle size of a singleflow, wherein the bandwidth and delay needs of each flow in the ONU ismet, and interaction between flows of the same or different servicegroups is eliminated. It is an effective solution to the problem withthe existing differentiated service model, e.g. there are different QoSfor different service classes, but the QoS for a single flow within eachservice class is ignored. Since the number of traffic flows handled byan access network is not very big, the present disclosure deliversabsolute QoS assurance for traffic in the ONU with a managementcomplexity that is acceptable to the network.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing illustrating one embodiment of a PONarchitecture.

FIG. 2 is a schematic drawing illustrating the architecture of anembodiment of the system of the present disclosure.

FIG. 3 is a flow chart depicting an embodiment of the method of thepresent disclosure.

FIG. 4 is a schematic drawing illustrating the scheduling and bufferqueuing within the scheduler of the present disclosure.

DETAILED DESCRIPTION

The disclosure provides a system and method for allocating bandwidth inremote equipment on a PON. Specifically, the OLT controls the acceptanceof traffic requesting the PON ONU for service, and the ONU classifies,shapes, and schedules the accepted traffic.

The present disclosure is described in greater detail below inconjunction with the accompanying drawings. The PON remote equipment ofthe present disclosure includes an ONU or ONT. The architecture of thesystem of the present disclosure is shown in FIG. 2. Taking an ONU as anexample, the system includes an OLT access permission control modulebuilt into the OLT and the ONU. The ONU of the present disclosure adoptsthe integrated service model and includes a classifier for checking andanalyzing the group headers of the arriving traffic based onclassification rules and separating the traffic. Wherein the classifierfirst groups the traffic accepted by the ONU into a correspondingservice class to prioritize the traffic so that different traffic gets adifferent service. To support different services, the present disclosuredefines three different service classes based on the IntServ model, andthe three classes are guaranteed service, controlled-load service, andbest effort service classes.

The guarantee service is to have guaranteed access to the bandwidth,delay restriction meeting the requirements of the traffic, and is theservice of the highest priority. As the traffic in the guaranteedservice class is sent first, the guaranteed service can be provided tovoice and time-sensitive flows. The controlled-load service is thetraffic that is serviced at a level similar to when there is not anetwork overload, even when there is a network overload. That is, thedata packet delay and packet loss are low for the traffic of this classwhen there is network congestion. The controlled-load service is theservice of the second highest priority. The best effort service is theservice of the lowest priority, and the traffic in this class is sentlast.

Once the grouped traffic is accepted by the ONU into the correspondingservice groups, the classifier checks and analyzes the group headers ofthe traffic group in different service classes based on thesource/destination address, source/destination port, the service classidentifier code, and the protocol, and separates the traffic in eachtraffic group. A separate buffer queue is established in the ONU foreach traffic in the guaranteed service class group and thecontrolled-load service class group to wait for service. All traffic inthe best effort service class group is mixed and is buffered in adefault queue to wait for service. The above classification rules areconfigured through the OLT access permission control module inside theOLT.

The ONU also includes a token bucket for shaping each buffered trafficin the guaranteed service class group and controlled-load service classgroup. The shaping operation is completed before queue scheduling. Onceshaped by the token bucket (σ_(i), ρ_(i)), there will be no burst in thedata flow and the data are queued at a controlled rate. The token bucketrestriction parameters, e.g. mean rate, ρ, and depth, σ, are configuredthrough the OLT access permission control module built into the OLT. Themean rate of the token bucket can be the mean rate of the traffic to beshaped and the depth of the token bucket can be the maximum packetlength of the traffic to be shaped.

The ONU also includes a scheduler, which includes an intra-classscheduler and an inter-class scheduler. The intra-class schedulerschedules traffic queues in the guaranteed service class group and thecontrolled-load service class group. The WFQ (weighted fair queuing)algorithm is used to schedule between traffic queues in the sameguaranteed service class group or controlled-load service class group,wherein each traffic queue is assigned a corresponding weight configuredby the OLT based on the characteristics of the traffic. The scheduledtraffic in the guaranteed service class group is sent to the firsttransmit priority queue, while the scheduled traffic in thecontrolled-load service class group is sent to the second transmitpriority queue. All traffic flows in the best effort service class groupare mixed in the first-in-first-out scheduler without intra-classscheduling by the intra-class scheduler, and are sent directly to thedefault transmit queue or the third transmit priority queue.

When the ONU's transmit timeslot arrives, the inter-class schedulerschedules between these transmit priority queues using the absolutepriority-based scheduling scheme. That is, the guaranteed service dataflows in the first transmit priority queue are first sent until thequeue is emptied, and then the controlled-load service data flows in thesecond transmit priority queue are sent, and the best effort servicedata flows in the default transmit queue or the third transmit priorityqueue are sent last.

The system also includes an OLT access permission control module, whichlimits the amount of traffic, N, accepted by and throughput, Y, of theONU, and configures, through signaling control, various parametersincluding classification rules used by the classifier in the ONU, tokenbucket restriction parameters, queuing weights used by the weighted fairqueuing scheduler, and buffer size.

The method of the present disclosure is implemented in the flow shown inFIG. 3 and includes the following steps:

Step 3-1: The OLT access permission control module controls theacceptance of the traffic and configures the classification rules usedby the classifier in the ONU, the token bucket restriction parameters,the queuing weights, and the buffer size used by the WFQ scheduler inthe ONU.

The OLT access permission control module checks the bandwidth usagestate of the ONU on a real-time basis. When new user service trafficrequests the ONU for service, the ONU reports the needed bandwidth, b,delay, d*, requirement, and other service traffic characteristicsthrough signaling to the OLT access permission control module. The OLTaccess permission control module determines whether the bandwidthcurrently available in the ONU can meet the bandwidth need of thetraffic, and if yes, determines that the ONU accepts the traffic andcalculates the guaranteed bandwidth, g_(i), and weight coefficient,φ_(i), for the accepted traffic using access permission controlalgorithm. Otherwise, the OLT access permission control moduledetermines that the ONU rejects the traffic. Alternatively, the OLTaccess permission control module proposes a parameter negotiation withthe user of the traffic through signaling and determines that the ONUaccepts the traffic if the bandwidth available in the ONU can meet thebandwidth requirement of the traffic after the negotiation.

In conclusion, the OLT access permission control module can limit theamount of traffic accepted by and throughput of the ONU. The accesspermission control algorithm also provides through signaling controlinformation about the configuration of various parameters, including theclassification rules used by the classifier in the ONU, the token bucketrestriction parameters, the service rate of the weighted queuingscheduler, and the weight coefficient assigned to each traffic flow.

Step 3-2: The traffic accepted by the ONU is classified by theclassifier.

The classifier first classifies the traffic accepted by the ONUaccording to the configured classification rules, wherein the classifierfirst groups the accepted traffic into the guaranteed service classgroup, the controlled-load service class group, and the best effortservice class group.

Then, the classifier checks and analyzes the group headers of theguaranteed service class group, the controlled-load service class group,and the best effort service class group using the configuredclassification rules, the source/destination address, thesource/destination port, the service class identifier code, and theprotocol. A separate buffer queue is established in the ONU for eachtraffic in the guaranteed service class group and controlled-loadservice class group to wait for service. All traffic in the best effortservice class group is mixed and buffered in a default queue to wait forservice.

Step 3-3: The token bucket shapes the traffic classified by theclassifier.

Once classified by the classifier, the traffic is shaped by the tokenbucket according to the configured token bucket restriction parameters.The token bucket shapes the individual traffic in the guaranteed serviceclass group and controlled-load service class group according to thetoken bucket parameters (σ_(i), ρ_(i)), where the token bucketparameters σ_(i), ρ_(i) are negotiated between the user and the OLTaccess permission control module through signaling. The mean rate of thetoken bucket, ρ, may use the mean rate of the traffic, and the bucketdepth may use the maximum packet length, L_(max), of the traffic. Oncethe parameters are negotiated, the user must send the traffic inaccordance with the negotiated parameters. If the user does not send thedata flows according to the negotiated parameters, the token bucket hasthe ability to limit the service data flows so that they are incompliance with the agreed flow parameters.

For example, when the data packets of arriving traffic are greater thanthe above token bucket depth, the traffic is not in compliance with thenetwork resource reserving protocol, and the data packets of the trafficwill be discarded. When there is a burst in the traffic, the above meanrate of the token bucket can limit the data packet outflow rate.

To sum up, shaping with the token bucket can suppress any traffic burstsand control the rate at which the traffic flows into the network.

Step 3-4: The scheduler schedules the classified and shaped traffic.

In the present disclosure, the queuing scheduler in the ONU adopts atwo-level buffer and queuing scheduling mechanism. The first levelscheduling is the intra-class scheduling, which is used only for trafficin the guaranteed service class group and the controlled-load serviceclass group. The second level scheduling is the inter-class scheduling,which is used among the three service classes, e.g. guaranteed service,controlled-load service, and best effort service classes.

The classified and shaped traffic queues, which fall in the guaranteedservice class group and the controlled-load service class group, arescheduled using the intra-class weighted fair queuing (WFQ) schedulingscheme, wherein each queue has a corresponding weight that is calculatedby the OLT access permission control module according to the bandwidthpreserved for and delay requirement of the traffic, and configured inthe scheduler through signaling. The value of the weight reflects thebandwidth available to the queue. By scheduling through the scheduler,it is ensured that each traffic is able to share the bandwidth inproportion to its weight and to get the service it deserves withoutbeing affected by other traffic, and hence the separation betweentraffic.

The above scheduling involves the following steps: The remote equipmentgroups the service data traffic in the queues and calculates the servicestart virtual time and service end virtual time of each data groupaccording to the group length and weight of the queue. At the time oftransmission, the queue having the smallest service end virtual time isselected from among the queues for transmission and the system virtualtime is updated. Then the remote equipment recalculates the servicestart virtual time and service end virtual time of all traffic queues inthe guaranteed service class group or controlled-load service classgroup and outputs the queue with the smallest recalculated service endvirtual time. The remote equipment repeats the above steps until allqueues are emptied.

Once out of queue, the traffic goes to the corresponding transmitpriority buffer queue. That is, the WFQ scheduled traffic in theguaranteed service class group is sent to the first transmit prioritybuffer queue, and that in the controlled-load service class group issent to the second transmit priority buffer queue. Therefore, thetraffic in the best effort service class group is mixed in the first infirst out (FIFO) scheduler without the WFQ scheduling and goes directlyto the default transmit buffer queue, e.g. the third transmit prioritybuffer queue.

In the ONU transmit timeslot, the absolute priority-based schedulingscheme is adopted to schedule between the three transmit priorityqueues, e.g. the traffic of the guaranteed service class group in thefirst transmit priority queue is sent first. When the first transmitpriority queue is emptied, the traffic of the controlled-load serviceclass group in the second transmit priority queue is sent. When thesecond transmit priority queue is emptied, the traffic of the besteffort service class group in the third transmit priority queue is sent.

In the above embodiment of the method of the present disclosure, theinternal queue scheduling and buffering by the scheduler is illustratedin FIG. 4.

The following further describes how the traffic in each service classgroup is handled. For the traffic of the guaranteed service class group,an absolute delay upper limit, d*, is needed. In an access network,there are propagation delays, transfer delays, queuing delays, andlatency delays caused by use of time division multiple access forupstream transfer. The propagation delay is associated with the linkservice rate. Though it is inevitable, it is negligible compared withthe other three delays as the link rate is usually high. The transferdelay is associated with the link length and link rate. Once the networkarchitecture is set, the transfer delay is relatively stable and isinevitable as well. For the queuing delay, the shorter the queue, thesmaller the delay. In the two-level queue scheduling scheme, the majorfunction of the intra-class traffic scheduling is to eliminateinteraction between traffic. As long as each queue gets a service rategreater than the arrival rate of the data packets, the queue willreceive timely service, and the queuing delay will be very small. In thepresent disclosure, the intra-class scheduling rate is determined by thereserved bandwidth calculated by the OLT access permission controlmodule. The reserved bandwidth is

$r = {\sum\limits_{i = 1}^{N}\; b_{i}}$

and the WFQ scheduler assigns a weight coefficient of φ_(i) to thetraffic that is in compliance with the token bucket parameters. Based onthe weight coefficient and the service rate of the scheduler, eachaccess traffic, f_(i), may be provided with a minimum service rate of

$g_{i} = {r\; {\varphi_{i}/{\sum\limits_{j = 1}^{N}\; {\varphi_{j}.}}}}$

When the intra-class scheduled data traffic group goes into the firsttransmit priority queue for transmission, the traffic of the guaranteedservice class group will be sent first upon arrival of the ONU transmittimeslot until the queue is emptied. Accordingly, the maximum delay atthe first level scheduling can be obtained, e.g.d_(i)*≦σ_(i)/g_(i)+L_(max)/r where his is the token bucket depth andL_(max) is the maximum packet length of the traffic.

The traffic of the controlled-load service class group does not have astringent requirement for delay boundary. As long as the traffic hasaccess to certain service bandwidth under any circumstances, the QoSwill not be significantly impacted by network congestion. The systemreserves certain bandwidth for each traffic in the controlled-loadservice class group based on the negotiation between the user andnetwork. In the first level weighted fair scheduling, the service rateequals to the sum of the bandwidth reserved for all traffic, e.g.

$r = {\sum\limits_{i = 1}^{N}\; b_{i}}$

and each single queue has the reserved bandwidth according to itsweight. When the ONU transmit timeslot arrives, sending of service dataflows in the controlled-load service class group starts after allservice data flows in the guaranteed service class group are sent. Thetransmit timeslot that the ONU gets depends on the bandwidth reservedfor the guaranteed service and the controlled-load service. As long asthere is no data burst, this can ensure that the bandwidth requirementrequired by the traffic in guaranteed service class and thecontrolled-load service class can be fully met. In the event of a databurst, the bandwidth for the best effort service traffic can be taken toensure the QoS for the traffic in the guaranteed service class andcontrolled-load service class.

The traffic in the best effort service class group does not have delayrequirement, and it is not necessary to ensure the QoS for a single flowof this kind of traffic. Therefore, the token bucket and the first levelscheduling are not needed here. What is required to ensure normalservice of this kind of traffic is to define a minimum servicebandwidth. When the bandwidth of best effort service in an ONU transmittimeslot is taken, the system will do its best to make it up in the nextONU transmit timeslot so that this kind of data are sent properly. Whenthe system is unable to meet the requirement of this kind of service orthere are too many service data packets in the default queue, the systemwill discard the service data packets in the default queue to relievenetwork congestion.

It should be understood that the above are only exemplary and notlimiting preferred embodiments of the present disclosure. Any alterationor substitutions that can be readily made by those skilled in the artwithout departing from the technical scope of the present disclosureshould be encompassed within the scope thereof. Therefore, thedisclosure is solely defined by the appended claims.

1. A system for allocating bandwidth to a plurality of remote equipmenton a passive optical network (PON) and comprising: an optical lineterminal (OLT) that controls the acceptance of traffic requestingservice by the PON remote equipment and, through signaling control,classifies, shapes, and schedules the traffic in the remote equipment;and wherein the remote equipment classifies, shapes, and schedules thereceived traffic based on the parameters configured by the OLT,allocates a bandwidth to the received traffic, and outputs the trafficin the scheduled order.
 2. The system of claim 1 wherein the remoteequipment comprises: a classifier for classifying the traffic andplacing the traffic of each service class into a corresponding bufferqueue; a token bucket for shaping the traffic buffered in the classifierbased on the token bucket restriction parameters configured by the OLT;and a scheduler that schedules the shaped traffic queues in each serviceclass based on the scheduling parameters configured by the OLT and thepreset scheduling algorithm, and outputs the traffic in the scheduledorder.
 3. The system of claim 2 wherein the service classes compriseguaranteed service, controlled-load service, and best effort service. 4.The system of claim 3 wherein the scheduler comprises: an intra-classscheduler that schedules the traffic queues in the shaped guaranteedservice group and the controlled-load service group through a weightedfair queuing (WFQ) algorithm, and places the traffic in the scheduledguaranteed service group into a first transmit priority queue, trafficin the scheduled controlled-load service group into a second transmitpriority queue, and traffic in the scheduled best effort service groupinto a third transmit priority queue; and an inter-class scheduler thatadopts the absolute priority-based scheduling for all transmit priorityqueues once the transmit timeslot of the remote equipment arrives,wherein the traffic in the first transmit priority queue is sent firstuntil all the traffic in this queue is sent, then the traffic in thesecond transmit priority queue is sent until all the traffic in thisqueue is sent, and finally the traffic in the third transmit priorityqueue is sent.
 5. The system of claim 1 wherein the remote equipmentcomprises an optical network terminal (ONT) or an optical network unit(ONU).
 6. The system of claim 1 wherein controling the acceptance oftraffic requesting service by the PON remote equipment and classifying,shaping, and scheduling the traffic are accomplished through an OLTaccess permission control module built into the OLT.
 7. A method forallocating bandwidth in passive optical network (PON) remote equipment,comprising: configuring, within the PON remote equipment, the parametersfor classifying, shaping and scheduling operations; and the PON remoteequipment classifying, shaping, and scheduling the received trafficbased on the configured parameters, allocating a corresponding bandwidthto the received traffic, and outputting the traffic in the scheduledorder.
 8. The method of claim 7 wherein the configuring comprises: theoptical line terminal (OLT) configuring, through signaling control, theclassification rules of the classifier, token bucket restrictionparameters, and weight parameters for weighted fair queuing (WFQ) of thePON remote equipment.
 9. The method of claim 8 wherein the configuringcomprises: the OLT checking the bandwidth use state of the remoteequipment and, when a traffic requests the remote equipment for service,the remote equipment reporting the bandwidth needed by the traffic tothe OLT through signaling; and the OLT determining whether the bandwidthavailable in the remote equipment can meet the bandwidth need of thetraffic, and if so, determining that the remote equipment accepts thetraffic; otherwise, determining that the remote equipment rejects thetraffic, or the OLT proposing a parameter negotiation with the userrequesting service of the traffic and determining that the remoteequipment accepts the traffic if the bandwidth available in the remoteequipment can meet the bandwidth need of the traffic after thenegotiation.
 10. The method of claim 7 wherein the classifying, shaping,and scheduling comprises: the remote equipment classifying the receivedtraffic into a guaranteed service group, a controlled-load servicegroup, and a best effort service group based on the classification rulesconfigured by the optical line terminal (OLT), and placing each trafficof the guaranteed service class and the controlled-load service classinto a separate buffer queue, while placing all traffic of best effortservice class into a default buffer queue; the remote equipment adoptingtoken buckets with different parameters for shaping each flow of thetraffic in the guaranteed service group and the controlled-load servicegroup based on the token bucket restriction parameters configured by theOLT; and the remote equipment scheduling shaped traffic in the sameservice group using a weighted fair queuing (WFQ) algorithm and placingthe traffic into corresponding transmit buffer queues, the remoteequipment scheduling the shaped traffic in different service groupsusing the absolute priority-based scheduling and outputting the traffic.11. The method of claim 10 wherein the adopting comprises: the tokenbucket having a mean rate equal to that of the traffic to be shaped anda depth equal to the maximum packet length of the traffic to be shaped.12. The method of claim 10 wherein the scheduling shaped trafficcomprises: the remote equipment scheduling shaped traffic queues in theguaranteed service group and the controlled-load service group using WFQwith each traffic queue assigned a weight configured by the OLTaccording to the characteristics of the traffic, and mixing the trafficof the best effort service group in the first in first out (FIFO)scheduler; the remote equipment placing the scheduled traffic in theguaranteed service group into a first transmit priority buffer queue,placing the scheduled traffic in the controlled-load service group intoa second transmit priority buffer queue, and placing the traffic of thebest effort service group into a third transmit priority buffer queue;and the remote equipment adopting the absolute priority-based schedulingfor all transmit priority queues once the transmit timeslot of theremote equipment arrives, wherein the traffic in the first transmitpriority queue is sent first until all the traffic in this queue issent, then the traffic in the second transmit priority queue is sentuntil all the traffic in this queue is sent, and finally the traffic inthe third transmit priority queue is sent.
 13. The method of claim 12wherein the scheduling shaped traffic queues comprises: the remoteequipment calculating the service start virtual time and service endvirtual time for all shaped traffic queues in the guaranteed servicegroup or control-load service group based on the weight configured foreach traffic queue by the OLT, and scheduling and outputting the queuewith the smallest service end virtual time and updating the systemvirtual time; and the remote equipment recalculating the service startvirtual time and service end virtual time for all traffic queues in theguaranteed service group or controlled-load service group, andscheduling and outputting the queue with the smallest recalculatedservice end virtual time; the remote equipment repeating therecalculating and rescheduling process until all queues are emptied. 14.The method of claim 8 wherein the classifying, shaping, and schedulingcomprises: the remote equipment classifying the received traffic into aguaranteed service group, controlled-load service group, and a besteffort service group based on the classification rules configured by theOLT, and placing each traffic of the guaranteed service class and thecontrolled-load service class into a separate buffer queue while placingall traffic of best effort service class into a default buffer queue;the remote equipment adopting a different token bucket with differentparameters for shaping each flow of the traffic in the guaranteedservice group, and controlled-load service group based on the tokenbucket restriction parameters configured by the OLT; and the remoteequipment scheduling shaped traffic in the same service group using theWFQ algorithm and placing the traffic into corresponding transmit bufferqueues, the remote equipment scheduling the shaped traffic in differentservice group using the absolute priority-based scheduling andoutputting the traffic.
 15. The method of claim 14 wherein the adoptingcomprises: the token bucket having a mean rate equal to that of thetraffic to be shaped and a depth equal to the maximum packet length ofthe traffic to be shaped.
 16. The method of claim 14 wherein thescheduling shaped traffic comprises: the remote equipment schedulingshaped traffic queues in the guaranteed service group andcontrolled-load service group using the WFQ with each traffic queueassigned a weight configured by the OLT according to the type of thetraffic, and mixing the traffic of the best effort service group in thefirst in first out (FIFO) scheduler; the remote equipment placing thescheduled traffic in the guaranteed service group into a first transmitpriority buffer queue, placing the scheduled traffic in thecontrolled-load service group into a second transmit priority bufferqueue, and placing the traffic of the best effort service group into athird transmit priority buffer queue; and the remote equipment adoptingthe absolute priority-based scheduling for all transmit priority queuesonce the transmit timeslot of the remote equipment arrives, wherein thetraffic in the first transmit priority queue is sent first until all thetraffic in this queue is sent, then the traffic in the second transmitpriority queue is sent until all the traffic in this queue is sent, andfinally the traffic in the third transmit priority queue is sent. 17.The method of claim 16 wherein the adopting comprises: the remoteequipment calculating the service start virtual time and service endvirtual time for all shaped traffic queues in the guaranteed servicegroup or control-load service group based on the weight configured foreach traffic queue by the OLT and scheduling and outputting the queuewith the smallest service end virtual time and updating the systemvirtual time; and the remote equipment recalculating the service startvirtual time and service end virtual time for all traffic queues in theguaranteed service group or controlled-load service group, andscheduling and outputting the queue with the smallest recalculatedservice end virtual time; the remote equipment repeating therecalculating and rescheduling process until all queues are emptied. 18.The method of claim 7 wherein the remote equipment comprises: an ONT oran ONU.